Process Flow From SAP Basis Prespective During Logon and Transaction

Process Flow (LOGON)

1. User requests
2. Dispatcher handles the request
3. Keeps in queue and assign WP based on FIFO
4. The work process gets the username, password, client, logon language and the task handler interprets and hand over the task to the database process.
5. The DB process checks the credentials of the user and provides the necessary authorizations to the process.
6. The entire information is copied into the user context which is referred as ROLL OUT. (The information is copied into Roll Area which is subsequently available for all the requests made by the user)

The user context remains until the user is logged out. The user context is displayed in the transaction SU56. If the user accesses other than the transactions in SU56 it is missing authorizations and displayed from the Tcode SU53 (Missing Authorizations

Process Flow (TRANSACTION)

1. User executes a transaction Eg: ME22N – Purchase Order (or) VA01 – Sales order
2. The request is handled by dispatcher and hand over to the work process.
3. Work process requires information that is not available in the work process. The work process copies the user related information into the task handler i.e. copy user context into the Task Handler. It is also referred as ROLL IN
4. Further processing continues